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John Zawahri, 23, who allegedly went on a shooting rampage that killed five people in Santa Monica, had a history of mental health issues and was withdrawn, law enforcement and former friends said. Kim Baldonado reports from Santa Monica on NBC4 News at 11 p.m. on Monday, June 10, 2013. (Published Tuesday, June 11, 2013)

The mother of a man who went on a deadly rampage through Santa Monica last week released a statement read by a neighbor on Monday saying she is mourning her family and struggling to "come to grips with the overwhelming sorrow that has befallen all of us."

"As may be assumed, I am in mourning for my family and for those who are also affected by this horrific tragedy over the past few days," wrote Randa Abdou, whose 23-year-old son, John Samir Zawahri, killed her other son, Christopher Zawahri, 24, and her estranged husband, Samir Zawahri.

On Friday, John Zawahri killed his father and brother at their Santa Monica home and set it ablaze, then went on a shooting rampage through the city, killing three others before police fatally shot him at the Santa Monica College library.

Albert Ramos, a friend of Christopher Zawahri, said he remembers John Zawahri becoming withdrawn after entering his teen years.

"When he was younger, he was just a normal kid," Ramos said, "and high school came and he just separated himself from everyone."

Also killed were Carlos Franco, a 68-year-old groundskeeper for Santa Monica College, and his daughter, Marcela Franco, 26.

An autopsy for John Zawahri was scheduled for Monday.

"I cannot express my great sadness for the families who are also suffering at this terrible time," Abdou wrote. "I do ask the media to please give me time to grieve and to come to grips with the overwhelming sorrow that has befalling all of us. Thank you."